1. Field of the Invention
The present invention relates to an ink-jet head having an energy generation element unit including an energy generation element for ejecting a liquid to perform printing on a printing medium and a driving element unit including a driving element for driving the energy generation element, an ink-jet cartridge loaded the ink-jet head, and an ink-jet apparatus employing the ink-jet head.
2. Description of the Related Art
An ink-jet printing method is a method for performing printing by ejecting an ink and/or a treatment liquid for adjusting characteristics of the ink through ejection openings arranged in an ink-jet head and by depositing the ink and/or the treatment liquid on a printing medium, such as a paper or so forth, and thus is advantageous for quite low noise and capability of high speed printing. Amongst, an ink-jet head of the type, in which a thermal energy is acted on a liquid for abruptly heating the liquid to generate bubble, and whereby for ejecting a liquid droplet of the liquid within a liquid passage through ejection openings by volume expansion by the bubble, and the liquid is introduced into the liquid passage from a liquid chamber upon quenching of the bubble, has advantages in high response characteristics to a printing signal and in ease of making to an ink-jet head having much more ejecting openings.
An external appearance of the energy generation element unit of the ink-jet head is shown in FIG. 11, and a partially cut-out condition thereof is also shown in FIG. 12. Namely, a heat generating resistor 102 serving an electrothermal transducer as the energy generation element is provided on an insulation layer formed on the surface of a substrate 101. Also, a not shown electrode for supplying a power to the heat generating resistor 102 is arranged. A liquid passage 103, to which the heat generating resistor 102 on the substrate, is opened to ejection openings 104 at one end, and is communicated with a common liquid chamber 105 at the other end. In the common liquid chamber 105, a not shown liquid tank separately provided to the ink-jet head is connected via a coupling member 106.
As shown, when the heat generating resistor 102 is assembled for each of the liquid passages 103 respectively communicated with ejection openings arranged in alignment for performing printing of a plurality of dots for the printing medium, simultaneously, it becomes necessary to control ON and OFF of power supply independently for respective heat generating resistors 102. For performing control for the driving element may be integrally assembled to the energy generation element unit 107, as set forth above, or, in the alternative, as shown in FIG. 13 and FIG. 14 which shows a sectional structure along line XIV--XIV, is electrically connected to the energy generation element unit 107 via the bonding wire 108.
However, when the energy generation element unit 107 is fixedly connected with the driving element 109 and the bonding wire 108, if failure is caused in any one of the heat generation resistor 102 and the driving element 109, the overall ink-jet head can become inoperative.
For solution of such problem, employing the driving element unit having the driving element shown in FIG. 15, there has been proposed an ink-jet head and an ink-jet apparatus employing the ink-jet head establishing electrical connection by making the driving element unit 110 and the energy generation element unit 107 separable, and tightly stacking connecting electrodes 111 and 112 to each other as shown in FIG. 16.
As shown in FIG. 16, in the ink-jet head, in which the energy generation element unit 107 and the driving element unit 110 are made separable and tightly stacked, the connecting electrodes 111 and 112 are provided in number corresponding to the heat generating resistor 102 actually ejecting the ink. In order to completely achieve the functions and performance as the ink-jet head, all of these connecting electrodes 111 and 112 are required to be certainly connected.
However, conventionally, it is possible to cause non-uniformity in the height and shape of the connecting electrodes 111 and 112 projecting from mating surfaces 113 and 114 of respective units 107 and 110, and to cause connection failure between the connection electrodes 111 and 112 at the occurrence of offset of acting point of compression force upon connection of the units 107 and 110 as shown in FIG. 17 which causes moment between the units 107 and 110 about the centers of the connection electrodes 111 and 112.